VERY SMALL FRICTIONAL FORCE MEASURING INSTRUMENT

PURPOSE:To measure a frictional force and an attracting force with high accuracy by forming a spring for measuring the frictional force and a pressing load acting on a probe from ceramics, making the spring an integral type parallel leaf spring system and building a two-staged parallel leaf spring. CONSTITUTION:A probe 32 is fixed to the upper surface of two-staged parallel leaf springs 33 and 34 and the quantity of the deformations of the leaf springs 33 and 34 are measured by displacement gages 35 and 36, respectively. An object 31 to be measured is fixedly mounted on a tripod 37 movable in three- dimensional directions X49, Y50 and Z51. Piezoelectric elements 38, 39 and 40 are provided on the tripod 37 in the directions X49, Y50 and Z51, respectively. In a measurement, a pressing force due to contact between the object 31 to be measured and the probe 32 is controlled by the spring 34, the quantity of its displacement is measured by the displacement gage 35 and the pressing force is obtained by multiplying the spring rigidity by the quantity of deformation. Then, when a given pressing force is obtained, the element 39 in the Y direction is driven and the surface of the object 31 to be measured is scratched by the probe 32. A force generated at this time is detected by the spring 34 and a frictional force is measured.